Thread cutter



D 26, 1950 G. N. KUMBERA 2,535,294

THREAD, CUTTER Filed April 10, 194'! Fig. I. Fig.2

TH 1H..

Inventor George N. Kumbera Patented a.. 26, 1950 UNITED STATES PATENT OFFICE THREAD CUTTER George N. Kumbera, St. Louis, Mo.

Application April 10, 1947, Serial No. 740,643

7 Claims. (Cl. 112-252) This invention relates to V improvements in thread cutter attachments for sewing machines.

An object of the invention is to provide an improved form of thread cutter attachment for sewing machines including a reciprocable plunger having a thread cutting blade on its lower end and an operating button on its upper end whereby when a seam has been run on the sewing machine, it will be a sim le matter to push in on the operating button to cause the thread cutting blade or knife to move downwardly to sever the thread from the work just completed.

Another object of the invention is to provide an improved thread cutting attachment for sewing machines comprising an L-shaped frame or housing having an arcuate guide. passage formed therein, together with a series of needle type roller bearings disposed in a bearing chamber at one side of said guide passage, and a fiat steel plunger band will be reciprocably mounted in said passage, the same being formed with a thread cutting blade upon its lower end and an operating button on its upper end with resilient means associated therewith for normally holding said'thread cutting blade or knife in raised position.

A further object of the invention is to provide an improved form of thread cutting attachment for sewing machines which will be detachably supported upon the presser foot bar whereby when piecework sewing is being done, said cutter may be quickly operated to cut the thread before starting to sew on another piece of work, rather than resorting to the practice of pulling on two interconnected pieces of work to break the connecting thread, which practice often causes the thread to break in the seams of the work or garment resulting in costly repairs or the returning of the defective garment by a dissatisfied purchaser.

Another object of the invention is'to provide an improved form of thread cutting attachment for sewing machines which will be highly eificient in operation and relatively inexpensive to manufacture and produce.

Other objects will appear as the description proceeds.

In the accompanying drawings which form part of this application:

Figure 1 is an end view of a portion of a sewing machine showing the improved thread cutting attachment supported thereon being partly broken away and in section to show the interior constrilction thereof;

Figure 2 is an end view of a portion of a sewing machine with the improved thread cutting attachment secured thereon, and

Figure 3 is a partial sectional view taken on the line 33 of Figure 1.

Like characters of reference are used throughout the following specification and the accompanying drawings to designate corresponding parts.

In carrying out the invention, there is provided and illustrated a sewing machine generally designated by the reference numeral 1 having a needle bar 2 and a needle bar guard 3. A needle 4 of usual construction is adapted to be reciprocably mounted for operation through the opening 5 in the needle opening plate 6, all of which mechanism is of usual construction.

A foot supporting bar 1 is provided at the rear of the needle :bar 2, and supports the usual bifurcated presser foot 8 on its lower end, means (not shown) being provided for raising and lowering'the same.

A transversely extending blade or knife receiving slot 9 is formed to the rear of the presser foot 8 and is adapted to receive and cooperate with the thread cutting mechanism forming the subject matter of the instant invention, and being hereinafter described in detail.

The thread cutting attachment comprises an L-shaped frame or housing generally designated by the reference numeral l0 having an enlarged central portion l l and horizontally and vertically extending integrally formed arms I2 and [3 respectively.

The frame or housing ID will be formed with an internally disposed passage [4 extending from the outer end of the horizontal arm I2 to the central portion ll of said frame where it will make an arcuate bend at l5 and will then extend downwardly terminating at the lower end of the vertical arm 13.

An arcuate chamber I6 will be formed adjacent the arcuate bend l5 of the passage I4 and will be in communication therewith, for receiving and supporting a plurality of needle type roller bearings H.

An enlarged recess i8 will be formed in the outer end of the arm i2 and will receive and house a coil spring [9 and the inner end or head 26 of the operating plunger 2| formed with an enlarged operating button 22 on its outermost end. A flat steel plunger band 23 is slidably and reciprocably mounted in the passage HI through the frame or housing I0 and has its upper end fixed to the head 20 of the operating plunger 2|. The hand 23 will be engageable with the needle type roller bearings IT to facilitate the operation thereof.

A laterally extending steel cutting blade or knife 24 will be formed integrally upon the lower end of the band 23, being adapted to be forced downwardly into the blade or knife receiving slot 9 formed in the base 25 of the sewing machine I when the blade or knife operating button 22 is pushed inwardly against the tension of the coil spring 19. As soon asthe pressure is released from the button 22, the spring 19 will raise the blade or knife 24 upwardly above its cooperating slot 9.

A cover plate 26 will be removably secured to the frame or housing It by means of the screw fasteners 27, while larger screw fasteners 28 will extend through the frame or housing H1 and through the presser button supporting bar 1 for attaching the thread cutter to the sewing machine I.

In operation, as soon as a seam is run, the gan ment or work is pushed backfrom'the needle to the rear of the presser foot and the operating.

button 22 will be pushed inwardly, thereby causing the cutter'blade'or knife "2% to move downwardly. into the slot 9, thereby severing the thread.

A V-shaped sharpened cutting edge 29 will be formed on the blade or knife 24 to prevent the thread from rollingor slipping from under the blade or-knife while the same is bein cut.

From the foregoing description, it will be apparent. that there has been devised and provided a highly efiicient form of'thread cutter attachment for sewing machines which will be relatively inexpensive tomanufacture and produce.

While the preferred embodiment of the instant invention has been illustrated and described, it will be understood that ltis not intended to limit the scope of the inventionthereto, as many minor changes in detail of construction may be resorted to without departure from the spirit of the in-- vention.

Having thus described my invention what I claim as new and desire to secure by Letters Patent of the United States is:

In combination with a sewing machine having a pressure foot supporting bar, a thread cutter detachably supported by said bar, saidcutter including an L-shapedhousing having a first down-v wardly depending leg and a second le carried by P the upper end of said first leg, said housing-hav ing a longitudinally curved passage extending through said first and second legs thereof, a flexible operating'band slidably and guidably mounted in-said passage, a thread cutter blade on the lower end of said band, and manually operable means for selectively reciprocating said band in said passage to move said cutter blade into and out of 'operating'position.

2. In combination with a sewing machine in-.

cluding a baseand a head mounted on said base,

a needle bar mounted on said head for movement towards and away from said base, a thread cutter.

detachably secured to said headv adjacent said.

needle bar, said cutter including an L-shaped housing having a first downwardly depending leg having the lower end thereof disposed in vertical spaced'relation to said base, and a secondleg carried by the upper end of said first leg, said housing having a longitudinally curved passage extending through said first and second legs thereof, a flexible operating band slidably and guidably mounted in said passage, a thread cutter blade on the lowerend of said band, said base: having a=s1ot therein definin a cutting edg manually operable means carried by said band for reciprocating said band in said passage to move said blade into and out of said slot, said blade slidably engaging said cutting edge as said blade is reciprocated into and out of said slot.

3. In combination with a sewing machine head including a needle bar and a presser bar disposed behind said needle bar, a thread cutter including an L-shaped housing attached to said head adjacent said needle bar and presser bar, said housing including a horizontally disposed leg paralleling the vertical plane defined by said needle bar and presser bar and a second vertically extending leg disposed behind said presser bar, said housing having a longitudinally curved passage extending through said first and second legs thereof, a flexible band slidably and guidably mounted in said passage, a cutter blade on the lower end of said band, and means attached to the upper end of said band for selectively reciprocating said band in said passage.

4. In'combination with a sewing machine head including a needle bar and a presserbar disposed behind said needle bar, a thread cutter including, an L-shaped housing attached to said head adjacent said needle bar and presser bar, said housing including a horizontally disposed leg. paralleling the vertical plane defined by. said needle bar and presser bar and a second 'verti-- cally extending leg disposed behind said presser bar, said housing having a longitudinally curved passage extending through said firstand second legs thereof, a'flexible band slidably and guidably mounted in. said passage, a laterally projecting 3.

' cutter blade on the lower end of said band extending perpendicular to the plane of said first and second legs, said blade intersecting the plane defined by said cutter .bar and said. presser bar;

5. The combination of "claim 3 including a plu-. rality. of needle type roller bearings disposed insaid passage in said housing. and engaging the curved portion. of said band.

6. A". thread cutter attachment for sewing' machines including an L-shaped housing having a first and a second leg extending therefrom," means for attaching said housing to a sewing. machine head with said first leg thereof'disposed in a horizontal position and with said sec.- ond leg in a downwardly extending position, said? housing having a longitudinally curvedpassage extending through said first and second leg thereof, a fiexibleband slidably and guidably mounted in said passage, means on the upper end of-said band for selectively reciprocating said band. in: said passage, and a cutter blade on the lower end of said band.

'7. 'The combinationofclaim 3'including a plurality of needle type. roller bearings disposed in said passage in said housing and engagingthm curved portion of said band, a laterallyprojecte ing cutter blade. on thelowerend. ofsaid band, said blade extending. perpendicular tosthe plane; definedb'y said first .and second legs of said: housing.

GEORGEzN." KUMBERA.

REFERENCES CITED The-following references'are of record in the file of this patent:

UNIT D TATES A NTS J Number Na e Dat 118,467; Ford Au -129i- 7-1- 1,123,721 Foster ,.L Jail. 511915?- 

